r  /   /  ,j    .     i   o    1 


Issued  Jin 


U.S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ENTOMOLOGY— CIRCULAR  No.  139. 

L.  O.  HOWARD.  Entomologist  and  Chief  of  Bureau. 


DAMAGE  TO  SUGAR  CANE  IX  LOUISIANA 
BY  THE  SUGAR-CANE  BORER. 


BY 


T.   C.    BARBER, 

/  and  Expert. 


jTO'.   :  GOVERNMENT   PRINTING  OFFICE   :   1011 


DOCUMENTS  QEPT 


U.S.  DEPOSITORY 


B  UREA  U  OF  ENTOMOLOGY. 

L.  0.  Howard,  Entomologist  and  Chief  of  Bureau. 
C.  L.  Marlatt,  Entomologist  and  Acting  Chief  in  Absence  of  Chief. 
R.  S.  Clifton,  Executive  Assistant. 
W.  F.  Tastet,  Chief  Clerk. 

F.  H.  Chittenden,  in  charge  of  truck  crop  and  stored  product  insect  investigations. 

A.  D.  Hopkins,  in  charge  of  forest  insect  investigations. 

W.  D.  Hunter,  in  charge  of  south  rn  fit  Id  crop  insect  investigations. 

F.  M.  Webster,  in  charge  of  cereal  and  forage  insecl  in  i  <  siigalions. 

A.  L.  Quaintance,  171  charge  of deciduous  fruit  insect  investigations. 

E.  F.  Phillips,  in  charge  of  bee  culture. 

D.  M.  Rogers,  in  charge  of  pn  r,  nting  spread  of  moths,  field  work. 
RoLLA  P.  Currie,  in  charge  of  editorial  work. 
Mabel  Colcord,  in  charge  of  library. 

Southern  Field  Crop  Insect  Investigations. 

W.  D.  Hunter,  in  charge. 

F.  C.  Bishopp,  H.  P.  Wood,  W.  V.  King,  G.  N.  Wolcott,  engaged  in  tick  investi- 
gations. 

W.  D.  Pierce,  J.  D.  Mitchell,  E.  S.  Tucker,  T.  E.  Hoi.loway,  G.  D.  Smith,  E,  A. 

McGregor,  Harry  Pinkus,  W.  A.  Thomas,  Thomas  Lucas,  engaged  in  cotton 

boll  weevil  iti  i  <  si  igations. 
A.  C.  Morgan,  G.  A.  Runner,  S.  E.  Crumb,  engaged  in  tobacco  insect  investigations. 
T.  C.  Barber,  C.  E.  Hood,  engaged  in  sugar-cane  and  rici  insect  investigati 
F.  C.  Pratt,  engaged  in  cactus  insect  most  igations. 
It.  A.  Cooley,  D.  L.  Van  Dine,  Wilmon  Newell,  A.  F.  Conradi,  C.  C.  Km  mb- 

h  \ak,  collaborators. 


Circular  No.  139. 

United  States  Department  of  Agriculture, 

BUREAU    OF    ENTOMOLOGY. 
L.  O.  HOWARD,  Entomologist  and  Chief  of  Bureau. 


DAMAGE   TO    SUGAR    CANE    IN    LOUISIANA    BY    THE 
SUGAR-CANE   BORER. 

(Diatrsea  saccharalis  Fab.) 

By  T.  C.  Barber, 

Agi  a'  and  Expert. 

(The  work  upon  which  this  circular  I  is  conducted  In  direct  cooperation  with  the  Louisiana 

Sugar  Experiment  Station,  Audubon  Park,  New  Orleans,  La.). 

[NTR<  >l>M   I  [ON. 

The  sugar-cane  borer  (Diatrsea  saccharalis  '  Fab.)  has  been  the  most 
serious  insect  enemy  of  sugar  cane  with  which  the  Louisiana  planter 
has  had  to  contend  for  many  years.  In  a  bulletin  of  the  Louisiana 
Experiment  Station  :>  Dr.  W.  C.  Stubbs  gave  an  exhaustive  account  of 
the  probable  source  of  introduction  in  1856,  in  cane  imported  from 
Soul  h  America,  lie  also  referred  to  numerous  cases  of  severe  infesta- 
tion which  occurred  at  various  times  previous  to  L880.  In  1880s 
Dr.  L.  ( ).  Howard  conducted  investigations  on  this  insect,  and  men- 
tioned that  the  first  specimen  was  sent  in  to  the  Department  of 
culture  at  Washington  in  L878.  lie  also  cites  several  instana  I 
previous  severe  infestation,  one  occurring  as  far  back  as  1857  "along 
the  Lower  Mississippi."  In  1893  Prof.  II.  A.  Morgan  published  a 
bulletin  on  the  "Sugar-Cane  Borer  and  its  Parasite,"  '  in  response  to  a 
demand  for  informal  ion  following  a  severe  outbreak  of  the  cane  borer 
in  L890.  Another  severe  outbreak  in  Louisiana  in  L900  was  foil* 
by  the  publication  of  Bulletin  70,  referred  to  above,  in  which  Dr. 
Stubbs  gave  the  first  statement  as  to  the  actual  amount  of  financial 
damage  caused  to  sugar  cane  bj  the  cane  borer  (p.  889).  In  t  lie  case 
of  one  factory,  where  fair  comparison  was  obtainable  between  cane 

form  which  attacks  the  stalks  of  corn,  previously  confused  wlth-DtaraM  taccharalu,  has  been  found 
'I    Q.  Dyarol  th  ;  to  a  news]  I  by  him  under  the 

name  Entomological  >.  vol.  22,  no.  "  ill.) 

Bui.  To.  2d  scr.,  La.  Exp.  stu..  llatou  Kongo,  La.,  1902,    W.  C. 
Stubbs  and  11    a.  Morgan. 
• 
'  Bui  9,  2d  set 

I    11 


'2  DAMAGE    TO    SUGAR   CANE   BY   THE   SUGAR-CANE    BOBER. 

uninfested  and  infested  for  a  number  of  consecutive  years,  he  esti- 
mated the  damage  at  $136,335  for  three  years  on  plant  cane  alone, 
or  $45,445  per  year,  nearly  $1,000  per  day  during  the  grinding  season 
for  this  one  factory.  When  it  is  considered  that  most  of  the  area 
devoted  to  cane  growing  in  Louisiana  is  infested  with  the  borer,  it  can 
easily  be  appreciated  from  the  above  figures  that  the  total  financial 
loss  must  be  enormous. 

One  of  the  special  lines  of  work  planned  by  Mr.  D.  L.  Van  Dine, 
when  the  laboratory  for  the  investigation  of  sugar-cane  insects  was 
established  by  this  Bureau  in  1910,  was  the  determination  of  the 
various  classes  of  injury  caused  by  the  cane  borer.  Observations  and 
experiments  were  conducted  by  the  writer  in  1910.  It  was  discovered 
that  the  borer  is  responsible  for  much  more  injury  than  is  apparent  at 
first  sight.  Its  harmful  work  begins  with  the  destruction  of  eyes 
of  seed  cane,  reducing  the  stand  during  the  following  year;  con- 
tinues through  the  growing  season  of  the  cane  by  stunting  its  growth, 
and  causing  damage  from  windstorms,  owing  to  the  weakening  of  the 
stalk  due  to  the  burrows  and  girdles;  and  ends  by  causing  a  much 
lower  percentage  of  juice,  which  is  again  of  a  much  poorer  quality  in 
infested  canes  than  in  uninfested  canes.  The  last  is  an  important 
form  of  injury,  which  appears  to  have  been  overlooked  by  investigators 
and  planters. 

Moreover,  the  holes  made  by  the  cane  borers  are  the  chief  means 
of  entrance  to  the  stalk  afforded  the  various  fungous  diseases  of 
the  sugar  cane.  The  tonnage  yield  per  acre  is  reduced  by  borers, 
and  the  average  weight  of  canes  otherwise  similar  in  appearance  is 
found  to  be  reduced  by  borer  infestation. 

These  points  will  be  explained  in  detail  under  the  following  head- 
ings: Injury  to  seed  cane;  injury  to  growing  cane;  injury  to  mature 
cane  and  juice. 

INJURY  TO  SEED  CANE  BY  THE  SUGAR-CANE  BORER. 

The  buds  of  cane  are  favorite  places  for  the  attack  of  the  young 
borers  while  the  stalk  is  growing,  due  to  the  softness  of  the  tissue 
compared  to  the  woodiness  of  the  rind  of  the  cane  stalk  in  other 
locations.  The  young  larvae  of  the  sugar-cane  borer  will  enter  the 
buds  or  eyes  of  the  cane,  and  in  nearly  every  ease  the  attack  will 
result  in  the  destruction  of  the  bud.  Frequently  canes  will  be  seen 
in  which  more  than  50  per  cent  of  the  buds  have  been  destroyed  by 
the  borer.  Of  course,  many  borers  enter  the  stalk  at  other  places, 
around  and  between  the  joints,  as  an  average  cane  will  contain  only 
from  (I  (o  15  joints,  while  canes  will  often  be  found  with  from  6  to  10 
borer  holes  in  a  single  joint.     In  nearly  every  case  of  severe  iufesta- 


DAMAGE   TO   SUGAB    <    \M     Bl     MM     ST7GAR-<    \  N I     BOBER.  6 

fcion,  however,  it  will  be  found  that  a  considerable  percentage  of  the 
eyes  has  been  desl  royed. 

In  order  to  secure  definite  data  as  to  the  extent  of  this  injury,  a 
number  of  borer-infested  canes  were  picked  up  at  random  from  a 
pile  of  cane  on  a  property  which  probably  represents  typical  condi- 
tions in  Louisiana.  The  eyes  were  then  counted  until  100  were 
reached,  and  the  number  of  injured  eyes  tinted.  No  attention  was 
paid  to  the  amount  of  borer  infestation  in  each  stalk,  beyond  ascer- 
taining: that  at  least  one  borer  hole  was  visible.  In  the  first  100  eves 
counted  23  had  been  destroyed  by  the  borers.  On  repeating  the 
above  experiment  it  was  found  that  is  eyes  had  been  destroyed  in 
the  second  lot  of  10  I,  making  a  total  of  11  eyes  destroyed  out  of  a 
total  of  200,  or  20.5  per  cent.  The  infestation  of  the  plat  from 
which  this  cane  was  secured  was  approximately  determined  at  53 
per  cent,  which  would  indicate  that  Over  10  per  cent  of  the  entire 
number  of  eyes  in  the  plat  had  been  destroyed  by  borers. 

The  e  feet  of  this  is  to  km  luce  the  stand  of  cane  the  following  year 
by  reducing  the  number  of  viable  eyes  in  the  planted  cane.  The 
borers  also  damage  the  seed  cane  to  a  certain  extent  by  absorbing  a 
considerable  amount  of  the  sap  or  juice  which  nature  intended  to  he 
used  to  nourish  the  buds  when  they  commence  to  grow,  but  this 
injury  probably  does  not  assume  much  economic  importance. 

INJURY    TO    GROWING    CANE    BY   THE    SUGAR-CANE    BORER. 

When  the  cane  sprouts  in  the  spring  a  certain  amount  of  damage 
is  done  to  it   by  the  larvaa  of  the  first  brood,  which  bore  into  the 

hearts  of  the  young  and  tender  si ts.     Very  frequently  the  terminal 

leaves  t  urn  yellow,  and  on  being  pulled  come  out  of  the  whorl  of  the 
plant  bodily.  Examination  reveals  the  fad  that  they  have  keen 
almost  cut  off  in  the  heart  of  the  plant,  and  often  the  small  worm  is 
found  in  the  excavation.  It  is  likely  that  this  source  of  injury 
causes  considerable  damage  to  the  stand  of  cane,  although  no  experi- 
ments have  yel  keen  made  to  determine  the  percentage  of  injury . 

Borers  are  also  responsible  for  very  considerable  damage  by  wind- 
storms. After  a  sm ere  windstorm  in  the  fall  the  observer  can  notice 
two  e  fects  upon  sugar  cane.  In  some  cases  the  cane  will  be  blown 
prostrate,  being  left  lying  nearly  horizontally  upon  the  ground.  In 
other  cases  many  of  the  stalks  are  broken  by  the  wind,  sometimes 
clove  to  the  ground,  sometimes  in  the  center  or  near  the  top  of  the 
cane.  In  the  case  of  cane  which  has  been  blown  over,  it  will  • 
become  more  or  less  upright,  and  in  anj  event  it  will  continue  growth. 
The  greatest  injury  produced  upon  it  i^  crooked  and  bent  stalks, 
which  are  troublesome  to  harvest. 


4  DAMAGE    TO    SUGAR   CANE    BY   THE   SUGAR-CANE    BORER. 

In  the  event  of  the  stalks  being  broken,  however,  the  damage  is 
very  different.  In  this  case  the  growth  of  the  cane  stops,  and  the 
buds  on  the  top  joints  below  the  fracture  sprout  and  commence  to 
glow.  The  process  of  growth  draws  upon  the  supply  of  sugar  stored 
in  the  parent  cane,  so  that  the  cane  is  not  only  prevented  from 
reaching  its  fullest  maturitj7,  but  also  stands  a  very  good  chance  of 
losing  a  percentage  of  the  sugar  already  stored  up  in  the  stalk. 

A  close  examination  of  a  cane  field  after  a  heavy  wind  will  show 
that  to  borer  injury  is  directly  due  the  great  majority  of  broken  stalks. 
A  cane  will  seldom  break  in  a  wind  unless  the  stem  has  been  phys- 
ically injured,  and  examination  of  broken  stalks  nearly  always  shows 
that  the  breaks  occur  at  a  borer  girdle  or  a  large  burrow  near  the 
surface  of  the  cane.  The  burrows  and  tunnels  in  the  stalks  frequently 
concentrate  upon  a  certain  joint,  with  the  result  that  it  will  be  mate- 
rially weakened  and  will  snap  off  at  the  slightest  provocation.  Many 
canes  are  literally  girdled  by  borers,  a  tunnel  being  made  just  inside 
the  rind  completely  around  the  cane  and  only  the  center  is  left  to 
hold  up  the  top. 

To  a  large  extent,  also,  borers  are  directly  responsible  for  the  spread 
of  fungous  diseases  in  sugar  cane.  In  order  that  the  fungus  may 
enter  a  plant  it  is  nearly  always  necessary  for  the  spores  to  settle  on 
an  excision  or  wound  in  the  rind  of  the  cane.  These  openings  are 
furnished  in  great  numbers  by  the  borer  holes.  Dr.  C.  W.  Edgerton,1 
in  "Some  Sugar-Cane  Diseases,  "  advises  that  all  "seed"  cane  showing 
external  evidence  of  borer  injury  be  thrown  out,  as  a  preventive  of 
fungous  diseases.  L.  Lewton-Brain  2,  in  considering  the  rind  disease 
( Melanconium  sacchari),  says: 

Whenever  it  is  possible  to  trace  the  discoloration  to  its  starting  point,  this  will 
always  be  found  to  be  a  wound  of  some  sort.  The  wound  may  be  a  borer  hole,  a  leaf- 
hopper  puncture,  or  a  wound  made  in  stripping,  the  borer  wounds  being  perhaps 
most  favorable  to  the  fungus,  especially  in  the  older  parts  of  the  stalk. 

INJURY  TO  MATURE  CANE  BY  THE  SUGAR-CANE  BORER. 

AMOUNT   OP  INFESTATION. 

In  order  to  determine  the  extent  of  borer  infestation  an  elaborate 
examination  of  canes  was  made  during  the  fall  of  1910.  The  gen- 
eral practice  was  to  examine  100  canes  across  each  end  of  a  plat  and 
100  canes  across  the  middle.  These  hundreds  were  divided  into  4 
groups  of  25  canes  each  at  different  points  in  the  row.  This  plan  \\  as 
modified  in  varying  degrees  as  circumstances  made  it  necessary  or 
advisable.  In  all,  the  infestation  was  approximately  determined 
in  9  plats  planted  to  cane.     Of  these  9  plats  3  were  in  stubble  and  6 

i  Bnl.  120,  La.  Exp.  Sta.,  p.  12,  1910, 

2  Bui.  7.  Hawaii  Sugar  Planters'  Association  Experiment  Station,  1907. 


DAMAGE   TO   SUGAB   CANE    BY   THE   SUGAB-CANE    BORER.  5 

in  plant  cane.     The  leasl  injury  t«>  a  cane  l>\  a  borerserved  to  throw- 
it  into  the  infested  column.     The  general  results  are  shown  in  Table  I : 

Tabli    1       Infestation  by  thi  sugar-cam  borer. 


of  cane. 


Number 

ISortT 

free. 

Ined. 

1,900 

603 

1,297 

1,100 

341 

3,000 

944 

2,050 

age  of  in- 
festation. 


Plant  cane. .. 
Stubble  cane. 
All  canes 


69 
68.63 


In  addition  to  the  canes  referred  to  in  the  table,  two  other  large 
lots  were  removed  from  the  plats  for  other  purposes  and  examined 
for  borer  infestation.  One  hundred  canes  were  taken  from  a  planl- 
cane  plat  for  determining  the  comparative  weights  of  infested  and 
uninfected  canes.  These  canes  were  infested  to  the  extent  of  72  per 
cent.  From  a  stubble  plat  734  canes  were  removed  for  determining 
the  effect  of  the  borer  upon  the  sugar  content  of  the  cane.  Of  these 
canes  393,  or  53.54  per  cent,  ^  ere  infested.  Both  of  these  experiments 
are  described  in  detail  elsewhere.  Adding  these  counts  to  the  pre- 
vious number  we  have  a  total  of  3,834  canes,  of  which  1,313  were 
borer  free  and  2,521,  or  65.75  per  cent,  were  infested  by  the  borer. 


i  \i!<>\  mi    rops 


In  five  instances  the  same  number  of  tops  as  of  canes  were  exam- 
ined and  showed  a  distinct  correlation  between  the  infestation  of  the 
two  parts  of  the  stalk,  the  infestation  in  the  tops  increasing  to  corre- 
spond with  the  increase  in  the  infestation  of  the  cane-.  This  is  \  n-\ 
suggestive  as  to  the  value  of  clean  burning  of  the  trash  after  removing 
cane  from  a  severely  infested  held.  The  data  on  this  point  are  given 
in  Table  II: 

Tabli    II      Infestation  of  tops  by  the  sugar-cant  b 


Varieties. 

Per  cent 
infestal  ion 
in  canes. 

Percent 

infestation 
in  to] 

Purple 

59 
79 
81 

5 

7 



D  ;i 

17 

i 

Purple 

31 

CEXTI  r  INI  BSTATION. 


That  ii  is  the  tendency  of  the  borers  to  seek  the  noddle  of  the  plat 
ia  suggested  by  the  fact  that  in  1  cases  the  highest  percentage  of 
infestation  was  found   in  that  portion,  while  in  only  l   case  was  the 


6  DAMAGE   TO   SUGAR    CANE   BY   THE   SUGAR-CANE   BORER. 

lowest  infestation  found  in  the  middle  of  the  plat.  On  the  other 
hand,  in  6  cases  out  of  7,  where  comparison  could  be  made,  the 
lowest  infestation  was  found  at  the  ends  of  the  plats.  It  may  be 
said  in  general  that  the  highest  infestation  will  be  found  in  the  most 
luxuriant  cane. 

CHARACTER    OF    INFESTATION'    IN'    PLANT    CANE    AND    STUBBLE    CANE. 

In  fall  plant  cane  the  majority  of  the  infestation  is  in  the.  upper 
half  of  the  cane,  while  in  stubble  cane  the  infestation  is  more  notice- 
able near  the  ground,  although  the  whole  stalk  is  more  or  less  infested. 
This  may  be  due  to  the  earlier  sprouting  of  the  stubble  cane  in  the 
spring,  thus  causing  it  to  be  liable  to  attack  from  the  early  broods 
of  borers-;  and  also  a  certain  number  of  borers  may  hibernate  in  the 
stubble,  thus  being  present  in  the  spring  to  infest  the  early  sprouting 
cane.  On  the  other  hand,  fall  plant  cane  does  not  appear  above  the 
ground  as  early  in  the  spring  as  stubble,  and  as  the  adults  that 
appear  in  the  seed  cane  are  too  delicate  to  dig  through  the  soil  to  the 
surface  they  perish  underground.  A  field  of  fall  plant  cane  may  be 
regarded  as  borer  free  in  the  spring,  and  will  become  infested  during 
the  following  summer  from  outside  sources,  probably  to  a  degree 
depending  upon  the  severity  of  infestation  in  the  surrounding  terri- 
tory. 

The  fact  that  the  most  evident  borer  injuiy  occurs  in  the  lower 
half  of  the  stalk  in  stubble  cane  makes  the  damage  greater  than  in 
plant  cane  for  several  reasons.  The  first  is  that  the  actual  mechanical 
injury  by  the  borer  is  in  the  lower  joints,  which  are  more  mature 
and  have  the  greater  sugar  content.  Again,  the  presence  of  the  borer 
burrows  and  tunnels  in  the  lower  joints  affects  the  flow  of  sap  to  the 
top  of  the  cane,  thus  interfering,  more  or  less,  with  the  growth  of  the 
whole  cane.  Also,  the  joints  near  the  base  of  the  plant  tend  to 
become  hard  and  woody  following  borer  attack,  thus  increasing  the 
percentage  of  fiber  and  decreasing  the  percentage  of  juice.  Inciden- 
tally the  latter  point  increases  the  difficulty  of  grinding,  as  was  called 
to  the  attention  of  the  writer  by  a  sugar-house  manager  attributing 
the  breaking  of  some  machinery  to  the  crushing  of  heavily  infested 
sugar  cane. 

EFFECT    "1     INFESTATION    UPON    THE    WEIGHT    "1     CANE. 

In  order  to  find  oul  the  effect  of  borer  infesl  at  ion  upon  the  weight 
of  cane,  100  stalks  were  picked  out  and  carefully  averaged  in  size. 
All  were  cut  off  the  same  length.  Xo  attention  was  paid  to  borer 
infestation  in  selecting  the  canes,  and  the  opinions  of  several  gentle- 
men were  consulted,  all  canes  larger  or  smaller  than  the  average 
being  thrown  out  and  replaced  by  others  until  on  examination  it 
was  impossible   to   select    canes  larger  or  smaller  than  the  others. 


DAMAG1     TO   SITGAB    CANE    Bl     I  111.    SI  G  \;:-<   \ 


These  canes  were  then  examined  for  borer  injury.  72  being  found 
infested  and  28  borer-free.  The  smallest  damage  to  a  cane  by  a 
borer  was  sufficient  to  place  it  among  the  infested  canes.  The  canes 
were  then  weighed,  with  the  results  shown  in  Table  III: 

[]       Effect  of  borer  attack  upon 


Number 

Weight 
of  canes. 

weigh) 

Of  canes 

per  ton. 

weighl 

borer. 

weight 
due  to 

borer. 

28 

103 

Pounds. 
3. 54 

565.0 

Pounds.     Pi 

Borer                                     

72 

For  fun  her  results  a  wagonload  of  cane  was  taken  to  the  sugar- 
bouse,  and  was  t  here  separated  into  two  lots,  infested  and  un infested. 
Of  the  734  canes,  393,  or  53.54  per  cent,  were  infested.  The  least 
injury  by  borers  placed  a  cane  in  the  infested  lot.  Each  lot  of  cane 
was  then  weighed  separately  on  platform  scales.  The  393  infested 
canes  weighed  694  pounds,  an  average  of  1.76  pounds  per  cane, 
while  the  341  borer-free  canes  weighed  626  pounds,  or  an  avera 
1 .8  I  pounds  per  cane. 

T  u;i .i     I  \ '.      i  •  borer  attack. 


Cunes. 

Number 
of  canes. 

Weight 

;e     Number 

weight      of  ennes 

per  cane,    per  ton. 

per  ton 
borer. 

weight 

borer. 

Borer-free 

341 
393 

694 

Pounds, 
1.84 
t.76 

1,087 
1,136 

Borer-infested 

4.31 

On  the  basis  of  Table  IV  the  difference  in  yield  between  borer-free 
and  borer-infested  cane  fields  would  amount  to  a  loss  of  aboul  I  ton 
of  cane  per  acre  when  the  borer-free  cane  gives  a  yield  of  25  tons 

per  acre. 

EFFECT  OF  BO  >N  I  n   tCE. 

The  following  series  of  experiments  was  carried  out  to  ascertain 
jusl  what  damage  the  cane  borer  inllicts  upon  the  cane  juice,  in 
add  it  ion  to  t  he  physical  damage  to  i  be  cane  plant : 

leriment  /.  Six  stalks  of  D.  71  cane  were  --elected,  three  being 
heavily  infested  by  the  borer  and  three  being  borer-free.  The  stalks 
were  cut  into  four  samples,  as  follows: 

(1)  :\\  bottom  joints,  borer-free  canes. 
'■'<\  bottom  joints,  borer-infested  canes. 
■'11  top  joints,  borer-free  canes. 
(4)  3}  top  joints,  borer-infested  canes. 


8 


DAMAGE    TO    SUGAR   CANE    BY   THE    SUGAR-CANE    BOEER. 


Samples  1  and  3  and  samples  2  and  4  were  thus  from  the  same  canes. 
Each  sample  was  carefully  weighed,  run  through  a  3-roller  hand 
mill,  and  the  weight  of  juice  from  each  sample  recorded.  The  juice 
was  then  analyzed,  the  latter  operation  being  kindly  performed  by  Mr. 
W.  G.  Taggart,  chemist  at  the  sugar  experiment  station. 

Sample  2  (bottom  joints)  showed,  compared  with  sample  1,  losses 
due  to  the  borer  of  4.59  per  cent  of  juice,  2.6  per  cent  total  solids, 
4  per  cent  sucrose,  and  12  per  cent  purity,  and  an  increase  of  solids 
not  sugar  of  0.8  per  cent. 

Sample  4  (top  joints),  compared  with  sample  3,  showed  losses  of 
7.27  per  cent  of  juice,  4.2  per  cent  total  solids,  4.9  per  cent  sucrose, 
and  13.7  per  cent  purity,  and  an  increase  of  solids  not  sugar  of  0.8 
per  cent.  It  can  thus  be  seen  that  the  borer  not  only  reduced  the 
juice  quantitatively  but  qualitatively  as  well  and  to  a  more  marked 
degree. 

Placing  these  figures  on  a  basis  of  1  ton  of  cane  to  the  sample, 
we  have  the  following  results:  Sample  2  showed  losses  of  91.8  pounds 
of  juice,  35.2  pounds  of  total  solids,  59  pounds  of  sucrose,  and  a 
percentage  loss  of  sucrose  of  34.04  per  cent.  The  increase  in  solids 
not  sugar  was  8  pounds  per  ton  of  cane.  Sample  4  showed  losses  of 
145.4  pounds  of  juice,  68.6  pounds  total  solids,  70.9  pounds  sucrose, 
and  46.43  per  cent  sucrose  actual  loss,  with  an  increase  of  solids  not 
sugar  of  5.4  pounds  per  ton.  The  average  production  of  the  total 
borer-free  cane  (samples  1  and  3)  was  163  pounds  sucrose  per  ton  of 
cane  and  of  the  total  infested  cane  (samples  2  and  4)  98.1  pounds 
sucrose  per  ton  of  cane.  This  gives  an  average  loss  of  64.9  pounds, 
or  39.81  per  cent,  of  sucrose  per  ton  of  cane  due  to  the  borer.  The 
results  of  this  experiment  are  given  in  tabular  form  in  Table  V. 


Table  V. — Analysis  <i 


if  sugar  cane  (D.  74)  to  determine  effect  on  sugar 
borer  injury  to  sugar  cane. 


con 


tent  of  the 


6 
P. 

o 

d 

Nature  of  sample. 

6 

1 
o 

o 

B 

.§, 
o 

'3 

a 

a 

02 

3 

T3 

v  C 

•- •  fc- 

-  o 

°  o 

w 

o 

Hi 

3 
w 

■a  . 

o  o 
O 

2« 

a 

•a 
a 

^a  o> 

si  § 

Hi 

09 

a 

o 
o 

a 

O 

.d 
t- 

O) 

o 
o 

3 

3 

3    . 

a. 5, 
£  a 

o 

a 

a 
o 
o 

M 

3 

o  C 

o  i. 

3  O 

.S3 

Z  i 

$•5 
►J 

1 

>> 
-*>   . 

3  t- 
BO 
"  3 

►J 

1 

3 J  bottom  joints  borer- 
free  canes 

Grams. 
1,512 

1,008 

1,282 

985 

Grans. 
419 

582 

783 

530 

62.  33 
57.74 
61.08 
53.81 

PjcI. 
4.  59 

7.27 

P.ct. 
16.6 

14.0 

16.1 

11.9 

P.ct. 
2.6 

4.2 

P.ct. 
1.3 

1.9 

1.4 

1.3 

9.3 
19.2 
12.0 

17.  1 

P.ct. 
1.4 

2.2 

2.2 

3.0 

P.ct. 
13.9 

9.9 

12.5 

7.6 

P.ct. 
4.0 

4.9 

83.7 
71.7 
78.6 
64.9 

P.cL 

2 
3 

3!  bottom  joints  borer- 
infested  runes 

3J    top   joints    borer- 

12.0 

4 

top   joints    borer- 
infested  canes 

13.7 

NOTE.— Samples  1  and  3,  2  and  4,  were  from  tbe  same  canes.    Each  sample  consisted  of  portions  of  three 
canes.    Analysis  made  Nov.  10,  1910. 


|i\.M  u;i     TO   SUGAB    CANI    Bl     Mil     SUG  \i:  I    \M     BOB]  R. 


Table  V.—Ana  D.  74)  of  the 

borer  injury  to  sugar  cam     Continued. 

BESUXTS   01     V.BOVE    \\\l . '.  \    BASIS  OF  1     io\    OF  CAN! 

I  1 1  !•:  SAMPLE. 


— 

§ 

- 

V 

0 

6 

Z 

Nature  of  sample. 

a 
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| 

"3 

M 

"3 

S3 

Pi 

Is 

III 

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c 

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3  a 

S3 

o 

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o  ~  = 

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p, 
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3     . 

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S3 

■9  B, 
o 

1" 

3 
•x 
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en 

O 

o 
3 

3    . 

6  c. 

S  3 
in  J 

=  9 

M    - 

S"3 

1 

;sj  bottoi 

2,000 

L6». 

Lbt. 

1 
171.7 

35.  -' 

Lbs. 
l&  2 

17.1 
l  1.0 

t6«. 

:,.7 

E6». 

17.4 
Hi'.  3 

5.  1 

Lbs. 

173.3 

1  l-l.  3 
152.  7 

si.  s 

/./..v. 

p.rt. 

2 
3 

3A  liotto 

:u  top  Joint 

J.  mm  1,154.8 

1,221.6 

01, 07ft  -' 

59.  i) 

34.04 

4 

joints  borer- 
1 1  i  /.  ■  t '  :     ini 

lit  ofsu- 
ton: 

■ 

163.  0 

Samples 2 and  I. . 

39.  "I 

1 

/•.>/' i  ri merit  2. — The  remarkable  figures  obtained  in  Experiment  1 
showed  the  advisability  of  conducting  a  further  experiment  upon  a 
larger  scale  in  order  to  obtain  more  conclusive  results.  For  this 
experimenl  30  canes  were  selected  ai  random  from  1).  71  cane.  Of 
these  n»  were  borer-free,  l<>  were  medium  infested  (1  to  3  joints  per 
cane  showing  borer  injury1,  .and  lit  were  heavily  infested  (5  or  more 
infested  joints  per  cane).  It  should  be  remarked  thai  the  infestation 
in  the  heavily  infested  canes  was  not  so  heavy  as  was  the  infestation 
of  samples  2  .and  -1  of  the  firsl  experiment,  in  which  every  joint  was 
infested.  Bach  sample  of  10  canes  was  separately  weighed,  run 
through  the  hand  mill,  and  analyzed  exactly  as  had  been  done  with 
the  samples  of  the  first  experiment.  The  analyses  were  again  made 
by  Mr.  W.  G.  Taggart.  The  results  obtained  fully  upheld  those  oi 
the  firsl    experiment. 

Sample  2  (medium  infested)  showed  losses  due  to  the  borer  of  0.3 
per  cent  juice,  l  per  cent  total  solids,  1.2  per  cent  sucrose,  2.2  per 
cent  purity,  and  an  increase  of  solids  not  sugar  of  0.1  per  cent. 
Sample  :i  (heavily  infested)  showed  losses  of  2.3  per  cent  juice,  3.4 
per  cent  total  solids,  L6  per  cent  sucrose,  I -'.7  per  cent  purity,  and 
an  increase  of  0.7  per  cent  solids  not  sugar. 

Reduced  to  a  basis  of  I  ton  of  cane  to  the  sample,  the  results  wore 
as  follows:  Sample  '_'  (medium  infested)  showed  losses  per  ton  of 
cane  of  6  pounds  juice,  13.19  pounds  total  solids,  L5.46  pounds 
sucrose,  8.78  per  cent  actual  loss  of  sucrose,  and  an  increase  in 
solids  not  sugar  of  ]  15  pounds.  Sample:;  (heavily  infested)  showed 
losses  per  ton  of  cane  of  46  pounds  juice.  17.85  pounds  total  solids, 


10 


DAMAGE    To    sn.AK    < '  A  X  F.    |;\     THE    SUGAR-CANE    BORER. 


60.72   pounds  sucrose,   and   an   increase  in  solids  not   sugar  of  7.73 
pounds. 

Comparing  the  percentage  loss  of  sucrose  in  the  heavily  infested 
cane  of  this  experiment,  34.51  per  cent,  with  the  average  loss  of 
samples  2  and  4  in  the  first  experiment,  39.81  per  cent,  and  con- 
sidering that  the  latter  cane  was  more  thoroughly  infested  than  the 
former,  it  will  be  seen  that  the  results  of  the  first  experiment  werenoi 
exaggerated  to  any  great  degree  by  reason  of  the  smallness  of  the 
samples.  The  complete  results  of  this  experiment  are  shown  in 
Table  VI. 


Table  VI. — Analysis  of  sugar  cane  (D.  74)  to  determine  effect  on  sugar  content  of  the 

borer  injury  to  cane. 


1 

Nature  of 

s 

C3 

o 

o 

u 

B 

*o 

o 

0) 

3 

s 

.s 

—    © 

■a  3 

+3 

So 

3 

•a 

aS 

o 

3 

I 

OS 

6 

'i7 

w     . 

o  C 

i  ~ 
3  o 
OS.Q 

3  2 

o 

sample. 

s 

"3 

O  0 

w;3 

*3  (U 

o 

VI 

o 

3" 

-/.   3 

— — 

o 

o 

3  ° 

>. 

a  o 
a; 

o 

01 

o 

O 

o 

8  8.2 

3 

3 

■- 

OS 

3 

«  - 

OS 

'A 

? 

£ 

p-i 

A 

r- 

J 

a 

a> 

0 

CO 

A 

- 

A 

Gms. 

Gms. 

P.ct. 

P.ct. 

P.  c(. 

P.ct. 

P.  «. 

P.  cf. 

P.ct. 

1 

Borer-free 

9,990 

6,  108 

61.1 

17.1 

1.6 

1.1 

11.1 

14.4 

84.2 

2 

Medium  infested 

11,081 

6,735 

60.8 

0.3 

16.  1 

1.0 

1.7 

1.2 

12.9 

13.2 

1.2 

82.0 

2.2 

3 

Heavily  infested 

8,824 

5,190 

58.8 

2.3 

13.7 

3.4 

2.1 

1.8 

21.4 

9.8 

4.6 

71.5 

12.7 

Note. — Each  sample  consisted  of  10  canes.  Each  of  the  medium-infested  canes  i  ontained  from  one  to 
three  infested  joints,  and  each  of  the  heavily  infested  canes  five  or  more  infested  joints.  Analysis  made 
Nov.  12,  1910. 

RESULTS    OF   ABOVE    ANALYSIS    FIGURED    ON   A   BASIS   OF   1   TON    OF    CANE    TO 

THE  SAMPLE. 


©" 

oi 

!j5S 

<r 

S3 

3 

C3 

j.^ 

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1 

3 

6 

Pi 

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Nature  of 

3 
'o 

3 
O 

3 -a 

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S 

■5  w  ■ 

X3  a> 

0J 

3    . 

3  o 
3  *-= 

"•go 

P. 

-   £ 
3  O 
10  .Q 

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sample. 

■s 

—     •- 

2° 

(O 

o 

3 

3 

S2 

Bk 

© 

=  3 

■ss* 

6 

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ago 

y;  O  X 

C3 
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Lbs. 

Lbs. 

£6s. 

LJs. 

£6s. 

£6*. 

Lbs. 

i&s. 

ite. 

Lbs. 

Z6s. 

P.  c/. 

] 

2,000 

1  ''22 

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19.55 

13.44 

L75.97 

2 

Medium     in- 

i  '1 

2,000 

1,216 

(i 

195. 77 

13. 19 

20.07 

1.12 

14.59 

1.15 

160.  51 

15.46 

!    8.78 

3 

Heavily     in- 

fested   

2,000 

1.  176 

46 

161.11 

47.  85 

24.69 

6.14 

21.17 

7.73 

115.25 

60.72 

34.51 

Experiment  3. — In  order  to  confirm  the  results  of  the  two  foregoing 
experiments,  and  also  to  secure  additional  accurate  data  upon  a 
larger  scale,  a  third  and  larger  experiment  was  conducted  early  in 
December,  1910.  A  wagonload  of  D.  7-4  cane  was  taken  to  the 
sugar  bouse  and  was  there  divided  into  two  lots,  borer-infested  and 
borer-free,  the  least  sign  of  borer  injury  throwing  a  cane  upon  the 
infested  pile.  Of  the  73  I  canes,  393,  or  53.54  per  cent,  were  infested. 
Each  pile  of  canes  was  loaded  separately  upon  a  wagon  and  weighed 
on  the  platform  scales.     The  393  infested  canes  weighed  694  pounds, 


DAMAi  iUGAB   <   \m:    By    i  li  I     SUGAB  i  A.1 


11 


an  average  of  L.76  pounds  per  cane,  and  the  34]  borer-free  canes 
weighed  626  pounds,  an  average  of  1.84  pounds  per  cane.  This  gi 
an  average  loss  in  weight  of  0.08  pound  per  cane.  In  1  ton  of  cane 
like  each  of  tJ  ese  samples  there  would  be  L,087  borer-free  canes  and 
1,136  borer-infested  canes;  or,  in  other  words,  it  would  require  49  m< 
infested  canes  to  make  a  ton  than  of  borer-free  canes.  On  a  (Too 
basis  of  25  tons  of  uninfested  cane  per  acre,  this  would  show  a  loss  of 
about  I  ton  of  cane  per  acre  due  to  the  borer. 

Each  lot  of  cane  was  then  run  through  the  mill  separately  and  a 
sample  of  the  juice  taken.  The  626  pounds  of  borer-free  cane  gave 
i:;i  pounds  of  juice,  or  68.85  per  (  enl  extraction,  while  the  694  pounds 
of  infested  cane  gave  155  pounds,  or  65.56  per  cent  extraction.  The 
loss  of  juice  due  to  the  borer  was  thus  3.29  per  cent. 

The  two  samples  df  juice  were  analyzed  by  Mr.  W.  (•.  Taggart,  and 
showed  a  loss  due  to  the  horer  of  I..")  per  cent  total  solids,  2.1  per 
cent  sucrose,  and  .").(i  per  cent  purity,  with  increases  of  0.1  per  cent 
glucose  ami  ti..",  per  cent  solids  not  sugar.  Figured  on  a  basis  of  I  ton 
of  cane  per  sample,  the  losses  are  66  pounds  of  juice,  30.69  pounds 
total  solids,  36.57  pounds,  or  19.33  per  cent,  sucrose,  and  increases  of 
0.72  pounds  glucose  and  5.17  pounds  solids  not  sugar.  The  results 
of  this  analysis  are  shown  in  Table  VII: 

Table  VI I      .  inalysis  of  su 

borer  injury  to  < 


9 

= 

o 

I 

= 

99 
O 

O 

a 
y. 

~    . 
-■  - 

"  a 

1- 

—  2 
GD  — 

Si 

"Z 

3 

o 

3 

to 

u 

-5 
■a  ■- 

O  3 

•A 

o 

A 

Id 

y-   3 

o 
Eh 

■d 
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•3  0 

3  g 

=  Z 

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o 

A 

C 

C3 

- 

= 
3_ 

3 
n 

3     . 

=  .=, 

"H 
*o 

d 

© 

V) 

0 

d 

o 
w 

O     . 

- 

3 

Purity. 

Nature 
of 

a 

u 

s 

ZL  *- 

"3  © 

M 

Mia 
^2 

Borer-free. 

1 

341 

Lbs. 
1.84 
1.76 

Lbs. 

Lbs. 
431 

P.ct. 

P.ct. 
16.  7 
15.2 

P.ct. 
1.5 

P.ct. 

1.0 

P.CI- 

2. 1 

2.0 

P.  r, . 
13.7 
11.6 

'i'i 

. 

P.ct. 
"5.6 

-The  above  sam  pi  n  load  which  was  taken  to  the  sugar  i 

1  infested  and 

injur 

LTS  OF  ABOVE  ANALYSIS  !  [Gl  RED  ON  A  BASIS  OF  1  TON  OF  CAN; 
THE  SAMPLE. 


.  re  of 

0* 

s 
u 

o 

"3 

^ 

S   E 

© 

3 

3 

n  - 

—  o 
o  — 

0     . 

-    ? 

i  pie. 

0 

o 

"" \0 

o 

«   O 

»3 

o 

a 

O   3 

=  o 

—    ^ 

u. 

'Z 

•s 

,d 
tx 
o 

O   O 

5 

3 

—  0 

2 
= 

5 

&•« 

CO 

■t. 

O 
3 

-; 

-    ^ 

Lo». 

Zos. 

Lbs. 

Lb*. 

2,000 

1,311 

199. 27 

30. 66 

34.08 

13. 1 1 

0.72 

152.08 

19. 33 

12  DAMAGE   TO   SUGAR  CANE   BY   THE   SUGAR-CANE   BORER. 

It  should  be  noted  as  having  a  bearing  on  all  of  these  analyses 
that  the  lower  the  purity  of  the  juice  the  lower  is  the  percentage 
of  total  sucrose  that  is  recoverable  in  the  form  of  sugar.  Therefore 
the  percentage  loss  of  sugar  in  the  impure  samples  somewhat  exceeds 
the  loss  of  sucrose.  The  sucrose  which  can  not  be  recovered  is 
approximately  equal  in  amount  to  the  glucose  present.  On  this 
basis  the  present  experiment  would  show  a  production  of  176.26 
pounds  sugar  per  ton  for  the  borer-free  cane,  while  the  borer-infested 
cane  would  give  138.97  pounds  sugar,  a  loss  of  37.29  pounds  per 
ton  of  cane,  equaling  a  loss  of  21.16  per  cent  sugar,  which  is  1.83 
per  cent  in  excess  of  the  sucrose  loss. 

It  may  be  computed  from  the  figures  in  Table  VII  that  an  acre  of 
borer-free  cane  yielding  25  tons  of  cane  of  the  above  quality  would 
yield  4,716.25  pounds  sucrose  per  acre,  while  if  it  were  infested  to 
the  same  degree  by  borers,  the  }ield  under  similar  conditions  would 
be  23.92  tons  of  cane  and  3,637.75  pounds  of  sucrose  per  acre — a 
loss  of  1,078.50  pounds  sucrose  per  acre. 

SUMMARY. 

The  sugar-cane  borer  damages  cane  in  the  field  by  destroying  a 
considerable  percentage  of  the  eyes,  thus  reducing  the  stand  of  plant 
cane;  by  stunting  the  growth  of  the  cane,  owing  to  the  physical 
injury  of  the  stem;  by  admitting  fungous  diseases  through  the 
wounds  in  the  stem;  and  is  the  main  cause  of  injury  by  the  wind, 
owing  to  the  weakening  of  the  stalk  due  to  the  tunnels  and  burrows. 
These  classes  of  injury  have  been  appreciated  by  planters.  It  now 
develops  that  there  is  another  and  very  important  class  of  injury 
which  has  been  overlooked.  This  is  the  reduction  of  botli  the 
quantity  and  quality  of  the  juice,  which  is  dealt  with  specially  in 
this  circular.  It  becomes  evident  that  both  the  planters  and  the  man- 
ufacturers are  vitally  interested  in  the  work  of  the  sugar-cane  borer. 
Investigations  of  methods  of  control  in  the  field  are  now  under  way. 
The  results  will  be  published  in  due  time.  In  the  meantime  planters 
are  referred  to  the  bulletin  on  the  subject  (Bulletin  70),  by  W.  C. 
Stubbs  and  H.  A.  Morgan,  of  the  Louisiana  Experiment  Station. 

o 


UNIVERSITY  OF   FLORIDA 


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